This film consists of three plots from the first three movies.
Eight Years Ago
In Highton View Terrace in 1992 before their adventure in the Digital World, siblings Tai and Kari Kamiya witness a Digi-Egg emerging from their computer. The egg soon hatches, revealing a Botamon. The Digimon rapidly digivolves into Koromon and then Agumon, who unintentionally destroys a good part of the neighborhood. A second Digi-Egg appears in the sky to reveal a Parrotmon. Agumon digivolves to Greymon, but brutally loses the battle. Tai revives Greymon with Kari's whistle, who defeats Parrotmon and disappears with him.
Four Years Later
In 1996, About six months after the DigiDestined departed from the Digital World, Izzy discovers a virus on the Internet infecting a Digi-Egg and rushes over to Tai's apartment to inform him about the newly-hatched Digimon, Keramon. Tai and Izzy monitor him until Gennai appears in a transmission from the Digital World, warning them about the dangers of his growth. He dispatches Agumon and Tentomon to stop the corrupted Digimon. When Keramon digivolves into Infermon, Tai furiously tries to alert the rest of the DigiDestined, but succeeds enlisting only the help of brothers Matt and T.K.
Agumon and Gabumon Warp Digivolve to WarGreymon and MetalGarurumon, prompting Infermon to Digivolve into Diaboromon, but they slow down because of the massive amount of e-mails being sent to Tai and Izzy. Diaboromon begins to duplicate himself and sets up a timer for 10 minutes as he forces the Pentagon to launch two nuclear missiles: one headed for Colorado, the other for the neighbourhood in Odaiba, Tokyo, Tai's neighborhood. Unable to accept defeat, Tai and Matt become digital and enter their computers to revive their Digimon. WarGreymon and MetalGarurumon gain the ability to DNA Digivolve to Omnimon, who easily defeats all but one Diaboromon. At one minute to go, Diaboromon is still too fast for them to hit, but Izzy forwards him the e-mails to slow him down. At the very last second, Omnimon impales Diaboromon through the head, disabling the missiles and killing him before the countdown is over. Unfortunately, the virus tracks down Willis and infects Kokomon as the segment ends.
Present Day
In 2000, While visiting Mimi in New York, T.K. and Kari witness a battle between Willis, Terriermon, and Wendigomon, Kokomon's corrupted Champion form . Wendigomon cryptically insists for Willis to "go back", to which he interprets as returning to Colorado. Kari, believing him to be in danger, e-mails Davis Motomiya and the other Digidestined for help in hopes of assembling in Colorado. Unfortunately, T.K. and Kari's train becomes derailed by Wendigomon on the way and they are unable to meet with the others.
Meanwhile, after taking planes and taxis, Davis, Yolei Inoue, and Cody Hida meet Willis in a truck. When Willis tries to get their group transportation to his house, the ride leaves without him and Davis; however, Davis devises a plan to get themselves to Colorado faster with the help of Raidramon. At the rendez-vous point, Davis, Yolei, and Cody began to question Willis' knowledge about Wendigomon. Hesitantly, Willis reveals that he created him and Diaboromon and thus assumes full responsibility of causing the viruses to affect them. However, Davis and Terriermon convince him to let them help, as they are friends and are on the same team.
At Willis's home the next morning, Wendigomon expectedly reappears, but Digivolves to Antylamon and easily defeats the DigiDestined. Once digivolved into Cherubimon, he proceeds to eat their Digimon, but T.K. and Kari arrive at the nick of time to provide back-up with Angemon and Angewomon. Angry, Cherubimon de-Digivolves the Digimon then de-ages the Digidestined, revealing that he wanted Willis to "go back" in time to when the virus first attacked him. To combat him, Angewomon and Angemon Digivolve to their Mega forms, Magnadramon and Seraphimon, to release two Golden Digi-Eggs for Willis and Davis. Veemon and Terriermon Golden Armor Digivolve to Magnamon and Rapidmon and allow themselves to be swallowed by Cherubimon. Inside, they see a manifestation of Wendigomon's true self, who begs them to destroy the virus. After doing so, Cherubimon is purified, but succumbs to his injuries and dies. After saying goodbye to his new friends, Willis and Terriermon walk back home to find Kokomon's Digi-egg on the beach.
